An analysis was done on varying designs for flexible links to determine how the mechanical properties of the link changed depending upon slight design changes. The analysis was performed by varying the length of the small tapered section center by a value based on its diameter multiplied by 0 to 6 times. The length of the center of the link was varied depending on the length of the ends (either 0.5" or 0.25") so that the overall height of the link remained at 3.5" with 0.5" ends and 3" with 0.25"ends. Algor's FEMPRO was used to perform bending and compression tests on the links with a one-pound load. From the deflections obtained, the stiffness of the links could be calculated in both bending and compression. From this the stiffness ratio could be found. For design purposes, the stiffness ratio had to at least greater than 5000:1 to ensure proper performance of the links in the dynamometer. Overall, all link variations obtained a ratio greater than 5000:1 excluding the shortest length link with 0x tapered section center. In addition, a stress analysis was performed on the links using FEMPRO. For this a proper mesh on the link had to be created in Cadkey and then imported in FEMPRO. Only a select few link were used in the stress analysis since the overall stress had little to no variation between different links. Overall, a stress of 43500 psi was obtained and this value did not change more than 300 to 400 psi in all the links tested.
National Research Council of Canada. Institute for Ocean Technology